Rail transportation is commonly used to move people and cargo. Trains of wheeled vehicles often provide a more efficient and timely means of travel than other forms of transportation. Material can be moved solely via rail, or can use rail transportation as a segment within an inter-modal system. Trains generally travel on one or more rails, but can also use other stabilization and directional devices, including electromagnetics.
Trains are powered by one or more locomotives or powered cars, and are usually controlled by an operator. The operator is generally present on board the train, although other arrangements are possible. Propulsion can be provided by a variety of on-board motors, including reciprocating engines, turbines, electric motors, diesel-electric systems or electromagnetic systems. The energy source can be carried on board the train in the form of fuel or battery power. Alternatively, the train can draw power from an external system, such as overhead power lines or an additional electrified rail near ground level.
The operator may control the train by manipulating manual controls or issuing vocal or electronic signals in a cab or a remote location. Trains may have a manual control mode where the train can directly respond to operator inputs regarding commands for applied throttle or other systems. Such a manual control mode may receive operator commands through a hand throttle, or other manual control. The operator may be located within the locomotive, or remotely relative to the locomotive.
Alternatively, the train may be operated by an automatic drive system (ADS). An operator may elect to engage the ADS over operating the train using manual commands. The ADS may determine train settings for applied throttle or other systems, and it may select these settings using pre-set algorithms that optimize train performance variables in light of various factors or functional preferences.
A train braking system, used to slow or stop the train, may also be controlled either manually or through an ADS. The braking system may use a pressurized brake pipe to control train braking. Alterations in the pressure within the brake pipe may allow a braking operation to occur. Such alterations may be triggered manually or by automatic systems.
Kane (U.S. Pat. No. 7,772,2134) discloses a “Failsafe Electronic Braking System for Trains.” Kane describes a system for activating a pressure valve on a brake pipe in response to an overspeed signal, a loss of power to the train control system or a braking signal from the cab or an alerter. However, Kane does not describe a braking system that activates braking in response to a sensed brake pipe pressure. Further, Kane does not describe a redundant brake pipe sensor that may also activate a braking operation.
Accordingly, there is a need for an improved braking system to ensure operability.